Polyacetal polysulfide polymers



Patented May 10, 1949 2,469,404 POLYACETAL POLYSULFIDE POLYMERS Joseph0. Patrick, Morrisvllle, Pa., asslgnor to Thiokol Corporation, Trenton,N. J., a corporation of Delaware No Drawing. Application August 29,1944, Serial No. 551,775

4 Claims. (Cl. 260-608) 1 This invention relates to polysulfidepolymers. Such polymers are characterized by recurring SS- linkages inthe chains thereof, each of Examples of the polythlo glycols or glycolpolysulfides are as follows:

the sulfur atoms of these linkages being firmly OHWHMSSCHMOH bound toadjacent carbon atoms. To these sulwhere n may Vary from 2 to 20 or morefur atoms additional loosely bound labile or iso- 2.oH.cH,.oH.cH,.ss.cmomcmon sulfur may be joined and the total sulfur ofthe H3 H3 linkages may vary from 2 to 6 atoms.

What has now become known technique for the 3 manufacture of thesepolymers comprises react- 0 Q G ing a soluble polysulfide with anorganic compound containing two carbon atoms to each of f S- -3 m whichis attached a substituent split 01f by said OH OH reaction. For example,a soluble polysulfide may be reacted with a dichloralkane, e. g.,ethylene fi fi fi dichloride or in general with an organic com- =-02-sS-CHLC (011,021 pound containing two carbon-attached substituo o entswhich substituents are split off by reaction with said polysulfide. sfor example Patrick 6. OH.CH2.CH7.0.CH.O.CHz.CHg.SS.CHz.CHz.OH Patents1,890,191, December 6, 1932; and 1.OH.CH2CH20.CH2.CH2.SS.CH2.CH2.0.CH2.CH2.0H 2,216,044, September 24,1940, and other Patrick patents, including 2,255,228, September 9, 1941.

The object of the present invention is to pro- 9 CHLCEOHLSSCHLORCHS videnew methods, techniques, and products in l or relating to the field ofpolysulfide and poly- H OH acetyl p y 1o. onsonacaomssonron. onion,

In accordance With the present invention, a H 6 monomeric organiccompound is prepared or pro- 1 vided which not only contains an -SS butalso 11. 3- 2.CHz-CH.CH2.SS.CH2.CH.CH2.CH:.CH3 is a glycol and maygenerically be defined as a 3D 6 glycol having two carbon atoms joinedto and separated by intervening structure characterized az- S-omoncmomomby an -SS- linkage, to each of which carbon OH OH atoms there isattached an alcoholic hydroxyl g p y also be defined as a g y 35 13.CH3.(|)H.CH3.SS.CHL |3H.CH2.CH:.CH:.CH| col or glycol polysulfide. 0H OThe monomeric organic compound so provided 14 y is then polymerized orcondensed with an alde- C CH .CH.CHz.SS.CHz.CH1 hyde. The resultingpolymeric product has a 6 6 dual character. It is a polyacetal polymerand, 40 since it has recurring SS- linkages, it is also 15. 0H; CH1 2.DOIBZSUlfide power. It may be identified as an Q Sg 11131101 organicpolyacetal polysulfide polymer. If the sulfur linkages are exclusively-SS- or sub- H H stantially so (and that is the preferred structure) Inthe above Compounds labile isosulfur may the product may be identifiedas a polyacetal dibe joined to the linkages so that the linksulfidepolymer. If formaldehyde is the conages may be densing agent, thecorresponding product is a s ss ss ss polyformal disulfide polymer. Thepolyacetal or r g g g g g polyformal polysulfide or disulfide may inaccord- H H H ance with this invention be reacted with a soluble s s Spolysulfide to obtain a further and different type These Co p y bidentified generically of polymerization and the resulting polymer may spoly h Y O O glycOl p y fi They be subjected to curing or vulcanizing ashereincan be prepared in a number of specifically differafter set forth.

ent Ways one of which may be indicated and illusas 1 above trated withreference to the compounds identified which may be described genericallyas dihydroxy dialkylene polysulfides. For example. dihydroxy diethyldisulflde may be prepared by reacting ethylenachlorhydrin with asolution of sodium disulflde. Sodium chloride is split off and thedense, through a disuliide linkage or bridge. Soluble polysulfides otherthan the disulfide may be used to obtain polythio glycols or glycolpolysulfides where the sulfide linkage contains more than two sulfuratoms, e. g., 3 to 6 sulfur atoms. By analogous procedure all of thepolythio glycols may be prepared.

In accordance with the invention, a compound falling within the broadgenus above described is reacted with an aldehyde. By this term is meantthe class of aldehydes .in general, including formaldehyde,acetaldehyde. propionaldehyde, butyraldehyde, and other aldehydes of thealkane series; aldehydes of the alicyclic series, aldehydes of theheterocyclic series as for example, furfuraldehyde commonly known asfurfural as well as aldehydes of the so-called aromatic or aryl series,as for example benzaldehyde and so forth. Ordinary formaldehyde in itsvarious forms, as for example, in the form of the well known commercialformalin as well as in other and modified forms, e. g.,paraformaldehyde, etc., is a highly reactive species of formaldehyde, isalso readily available commercially and cheap and may be employed withadvantage.

The following specific example is given purely to illustrate theprinciples of the invention which have been described and will bedefined in the claims.

Example 2 mols of ethylene chlorhydrin (161 grams of the anhydrousmaterial) are reacted with 500 cc. of a 2-molar solution of NaaSz byslow addition of the chlorhydrin to the stirred polysulfide solutionkeeping the temperature between 30 and 40 C. After the addition of thechlorhydrin is complete, the temperature is raised to about 80 C. andagitation is stopped. The heavy oily reaction product (dithio glycol) issettled out, removed to a separatory funnel and treated with its ownvolume of benzene and washed once with water to remove salts. Afterseparation from the water layer, the benzene solution is treated with 1mol of paraformaldehyde and heated from about 80 to 90 C. in thepresence of about 0.01

mol of hydrochloric acid. This operation is best ,performed in anesterification flask equipped with a reflux condenser and water trap sothat the benzene can be continuously returned to the reaction fiask andthe water formed can' be withdrawn from time to time. weight polyformaldisulfide is formed as a result of the above operation over a period offrom 10 to 12 hours. When approximately the theoretical amount of waterhas been formed, 1 mol in this case, the benzene is distilled off. The

product is a highly viscous liquid. Instead of distilling oil thebenzene as above stated, refluxing may be continued for say six hours,to obtain further polymerization of the polyformal polysulfide, and thebenzene then may be removed by distillation.

At this point the product obtained as above described and which may bereferred to as a water insoluble polyformal polysulfide is a highlyviscous liquid and may be used as a plasticizer for various syntheticresins, plastics, and products dihydroxy diethyl radicals conof arubber-like nature. It may also be used for impregnating porousmaterials such as organicand inorganic textile fabrics to render thesame water-proof. A further and special use of this oily reactionproduct lies in the field of high pressure lubricants. Tests made in ahydraulic press when this oil was placed between parallel steel platesshowed that it possesses very great resistance to diplacement under highpressure. For this purpose the product can be used as such or dissolvedin a solven v Instead of the particular polythio glycol used in theabove example, glycols in general having two carbon atoms to each ofwhich a hydroxyl group is attached, said carbon atoms being joined toand separated by intervening structure characterized by an -SS- linkage,may be used.

Instead of the particular aldehyde employed in the above example,aldehydes in general may be employed as above stated, in which casepolyacetal polysulfides will be formed.

By reacting mixtures of chlorhydrins, e. g., a mixture of ethylenechlorhydrin and propylene chlorhydrin with a soluble polysulflde,mixtures of polythio glycols can be obtained and reacted with analdehyde or mixture ofaldehydes. Indeed, mixtures of any two or more ofthe above polythio glycols or other polythio: glycols em- A highmolecular.

braced within the definition herein given may be reacted with aldehydes,thus producing copolymeric polyacetal polysulflde polymers. A singlealdehyde may be reacted with such a. mixture or a mixture of aldehydesmay be so reacted.

The various glycerol chlorhydrins may also be reacted with solublepolysulfides to produce polythio glycols or glycol polysulfides andthese may be reacted with formaldehyde or other aldehydes, as such or inadmixture with anyother polythio glycols, to make polyacetal polymerswhich may beused as such or reacted with soluble'polysulrides to obtainthe further polymer formation hereinbelow described.

After the completion of the condensation reaction as above described, afurther and different kind of condensation or polymerization may be 1empirical molecular weight of the polyformal polysulfide derived inExample 1 is dispersed in water by any suitable means, e. g., by the useof a high-speed agitator and a dispersion agent, if necessary, and theaqueous dispersion so obtained is treated with an equal molar ratio of,for example, sodium tetrasulfide and heated with a itation for a periodof 1 hour, after which the dispersion is allowed to settle and thesupernatant liquid is withdrawn. The dispersion can be readily washed.by repeating treatment with water with intermediate settling out of theinsoluble dispersion. When 'sufllciently purified, the material istreated with acid which causes coagulation to a rubber-like mass.

At this point the product may be used as a soft rubber-like coatingmaterial and for various other purposes. It possesses, nevertheless, thespecial property of reacting with vulcanizing or and different kind of ccuring agents and when so treated undergoes a transformation whereby anumber of useful properties are developed, including marked increase inmechanical strength and resistance to solvents and chemicals. In otherwords, a transformation occurs which bears an analogy to thevulcanization of rubber. No sulfur is, however, necessary to effect thesaid vulcanizing or curing, the curing agents being generally of anoxide or oxidizing character, as for example, zinc oxide, lead oxide,cupric oxide, lead peroxide, etc.

Purely by way of example, the following illustrations is given of thecuring operation. A compound is made according to the following formula:

Parts by weight Polymeras above obtained 100 Lead oxide Carbon'black 40These various ingredients are incorporated, pref- 2. Process whichcomprises heating formaldehyde with a glycol having the formulacondensing the formaldehyde and said glycol and REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,199,361 Lincoln Apr. 30, 19402,246,321 Rosen June 17, 1941 2,295,760 Schreiber Sept. 15, 1942-2,320,819 DAlelio June 1, 1943 2,347,436 Root Apr. 25, 1944 OTHERREFERENCES Gams et al., Melamine-Formaldehyde Con-.

densation Products, British Plastics, Feb. 194 pages 508-520.

